package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.redisson.misc.Hash;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.*;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private RabbitTemplate rabbitTemplate;
    @Resource
    private RedissonClient redissonclient;
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT; // 读取lua脚本

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    private IVoucherOrderService proxy;

    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户id
        Long userId = UserHolder.getUser().getId();
        //订单id
        long orderId = redisIdWorker.nextId("order");
        //1.执行lua脚本（判断购买资格，发送消息到消息队列）
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(), String.valueOf(orderId)
        );
        //2.判断结果是否为0
        int r = result.intValue();
        if (r != 0) {
            //2.1 不为0，没有购买资格
            return Result.fail(r == 1 ? "库存不充足" : "不可重复下单");
        }

        VoucherOrder voucherOrder=new VoucherOrder();
        voucherOrder.setId(orderId);
        voucherOrder.setUserId(userId);
        voucherOrder.setVoucherId(voucherId);

        //3.获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();

        //4.异步下单
        rabbitTemplate.convertAndSend("exchange.order","routing.order",voucherOrder);

        //5.返回订单id
        return Result.ok(orderId);
    }

    /**
     * 处理订单
     * @param voucherOrder
     */
    public void handleVoucherOrder(VoucherOrder voucherOrder) {
        //1.获取用户
        Long userId = voucherOrder.getUserId();
        Long voucherId = voucherOrder.getVoucherId();
        //2.获取锁对象
        RLock lock = redissonclient.getLock("lock:order:" + userId);
        //3.获取锁
        boolean isLock = lock.tryLock();
        //4.判断是否获取锁成功
        if (!isLock) {
            //获取锁失败，返回错误或重试
            log.error("不允许重复下单");
            return;
        }
        try {
            //代理对象执行订单创建
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            //释放锁
            lock.unlock();
        }
    }

    /**
     * 创建订单
     * @param voucherOrder
     */
    @Override
    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //4.一人一单
        Long userId = voucherOrder.getUserId();
        //4.1查询订单(根据userId和voucherId)
        Integer count =
                query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        //4.2判断是否存在
        if (count > 0) {
            //用户已经购买过
            log.error("用户已经购买过一次");
            return;
        }
        //5.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock=stock-1") // set stock=stock-1
                .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock", 0) // where id=? and stock>0
                .update();
        if (!success) {
            //扣减失败
            log.error("库存不足");
            return;
        }
        //6.创建订单
        save(voucherOrder);
    }

    /*@Override
    public Result seckillVoucher(Long voucherId) {
        //1.查询优惠卷
        SeckillVoucher seckillVoucher = seckillVoucherService.getById(voucherId);
        //2.判断时间
        if (seckillVoucher.getBeginTime().isAfter(LocalDateTime.now())) {
            return Result.fail("秒杀尚未开始");
        }
        if (seckillVoucher.getEndTime().isBefore(LocalDateTime.now())) {
            return Result.fail("秒杀已结束");
        }
        //3.判断是否充足
        if (seckillVoucher.getStock() < 1) {
            return Result.fail("库存不足");
        }

        Long userId = UserHolder.getUser().getId();

//        分布式版
        //获取锁对象
        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonclient.getLock("lock:order:" + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        //判断是否获取锁成功
        if (!isLock) {
            //获取锁失败，返回错误或重试
            return Result.fail("不允许重复下单!");
        }
        try {
            //获取代理对象（事务）
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }

//        单体版
        /*synchronized(userId.toString().intern()) {
            //获取代理对象（事务）
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        }
    }*/

    //以下为：redis消息队列版
    /*@Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户id
        Long userId = UserHolder.getUser().getId();
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString()
        );
        //2.判断结果是否为0
        int r = result.intValue();
        if (r != 0) {
            //2.1 不为0，没有购买资格
            return Result.fail(r == 1 ? "库存不充足" : "不可重复下单");
        }
        //2.2 为0，有购买资格，把下单信息保存到阻塞队列（异步下单）
        VoucherOrder voucherOrder = new VoucherOrder();
        //2.3订单id
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        //2.4用户id
        voucherOrder.setUserId(userId);
        //2.5优惠卷id
        voucherOrder.setVoucherId(voucherId);
        //2.6放入阻塞队列
        orderTasks.add(voucherOrder);

        //3.获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();

        //4.返回订单id
        return Result.ok(orderId);
}*/
    //    //线程池
//    public static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();
//
//    @PostConstruct // 注解PostConstruct：当前类初始化为完毕，就执行此方法
//    private void init() {
//        //下单
//        //SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
//    }
//
//    //阻塞队列 - 存储订单
//    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
//
//    //开启独立线程，实现下单任务
//    private class VoucherOrderHandler implements Runnable {
//        String queueName = "stream.orders";
//
//        @Override
//        public void run() {
//            while (true) {
//                try {
//                    //1.获取消息队列中的订单消息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS stream.orders >
//                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
//                            Consumer.from("g1", "c1"),
//                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
//                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
//                    );
//                    //2.判断消息获取是否成功
//                    if (list == null || list.isEmpty()) {
//                        //如果获取失败，说明没有消息，继续下一次循环
//                        continue;
//                    }
//                    //3.解析消息中的订单消息
//                    MapRecord<String, Object, Object> record = list.get(0);
//                    Map<Object, Object> values = record.getValue();
//                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
//                    //4.如果获取成功,可以下单
//                    handleVoucherOrder(voucherOrder);
//                    //5.ACK确认 SACK stream.orders g1 id
//                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
//                } catch (Exception e) {
//                    log.error("处理订单异常,{}", e);
//                    handlePendingList();
//                }
//            }
//        }
//
//        private void handlePendingList() {
//            while (true) {
//                try {
//                    //1.获取pending-list中的订单消息 XREADGROUP GROUP g1 c1 COUNT 1 STREAMS stream.orders 0
//                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
//                            Consumer.from("g1", "c1"),
//                            StreamReadOptions.empty().count(1),
//                            StreamOffset.create(queueName, ReadOffset.from("0"))
//                    );
//                    //2.判断消息获取是否成功
//                    if (list == null || list.isEmpty()) {
//                        //如果获取失败，说明pending-list没有消息，结束循环
//                        break;
//                    }
//                    //3.解析消息中的订单消息
//                    MapRecord<String, Object, Object> record = list.get(0);
//                    Map<Object, Object> values = record.getValue();
//                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
//                    //4.如果获取成功,可以下单
//                    handleVoucherOrder(voucherOrder);
//                    //5.ACK确认 SACK stream.orders g1 id
//                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
//                } catch (Exception e) {
//                    log.error("处理pending-list订单异常,{}", e);
//                    try {
//                        Thread.sleep(20);
//                    } catch (InterruptedException ex) {
//                        log.error("休眠异常:{}",ex);
//                    }
//                }
//            }
//        }
//    }
//
//    /*//阻塞队列 - 存储订单
//    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
//    //开启独立线程，实现下单任务
//    private class VoucherOrderHandler implements Runnable {
//        @Override
//        public void run() {
//            while (true) {
//                try {
//                    //1.获取阻塞队列中的订单消息
//                    VoucherOrder voucherOrder = orderTasks.take();//take获取阻塞队列的队首元素
//                    //2.创建订单
//                    handleVoucherOrder(voucherOrder);
//                } catch (InterruptedException e) {
//                    log.error("处理订单异常,{}", e);
//                }
//            }
//        }
//    }*/
//
}
